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2007 Research Technical Summaries

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2007 Technical Summaries

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bridge with crack

Bridge Research

Putting Research into Practice: Implementing a Fatigue Detail Classification Scheme for Mn/DOT’s Steel Bridges

This project implements research that classifies steel bridges based on the frequency and severity of fracture and fatigue-sensitive details that are present in each bridge. The gross ranking of bridges with high, medium or low need for preventive maintenance or special inspection will be stored in Pontis, Mn/DOT’s bridge management database, for use by bridge inspectors and those responsible for managing Minnesota’s bridges.


Technical Summary: 2007084TS (PDF) | Full Report: 2007-22 (PDF)


“This conceptually simple idea—gathering and classifying data from bridge plans and inspection records—means that important information will be readily available to help Mn/DOT manage its steel bridge inventory.”

– Jim Pierce, Mn/DOT Bridge Management Engineer

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freeway traffic density graphsRamp Metering

Improving Minneapolis/St. Paul’s Ramp Metering System for Smoother Traffic Flow

To streamline traffic flow and reduce backups on Twin Cities highways, Mn/DOT engineers researched ways to improve the algorithm they use to estimate queue size on entrance ramps and calculate minimum rates for releasing cars from ramps to highways. More than 20 parameters were tested through computer simulations. The new optimized algorithm and ramp-monitoring system increases average speed and reduces travel time and energy consumption.


Technical Summary: 200751TS (PDF) | Full Report: 2007-51 (PDF)


“Making improvements to the ramp metering system on Twin Cities freeways will reduce travel time, save fuel and improve safety on the mainline while maintaining acceptable delays at the ramp.”

– Todd Kramascz, Operations Supervisor, Mn/DOT Regional Transportation Management Center

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The Peak-Pick program can analyze multiple files at once, saving time and improving accuracy.Pavement Testing Software

Developing a Computer Program to Select Peak Dynamic Sensor Responses from Pavement Testing

In order to better analyze the vast amounts of pavement response data that Mn/DOT collects, investigators updated and enhanced Mn/DOT’s Peak-Pick software program. The updated version is more robust and efficient, and provides multiple ways to analyze the data.


Technical Summary: 200749TS (PDF) | Full Report: 2007-49 (PDF)


“With the new program, you open it up, select as many data files as you want, press ‘go,’ and it’s off. The new version is faster, more efficient and has made great strides in reducing noise in the data, providing more accurate results.”

– Tom Burnham, MnROAD Senior Road Research Engineer

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Investigators load-tested two 30.5-foot end sections of an 88-foot girder from Mn/DOT bridge 73023, both with and without a bridge deck, measuring strain, compression, displacement and cracking.Bridge Design

Shear Capacity of Prestressed Concrete Bridge Girders

Design specifications of shear reinforcement requirements in prestressed concrete bridges have changed significantly. Researchers load-tested to failure a girder that was built to older design codes and evaluated its shear capacity. They also examined how to judge the shear capacity of other bridges designed to older specifications.


Technical Summary: 200747TS (PDF) | Full Report: 2007-47 (PDF)


“The design requirements have changed to include much more shear reinforcement. We want to make good decisions about the safe operating load of these older bridges.”

– Yihong Gao, Bridge Designer, Mn/DOT Office of Bridges

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inflatable plug in stormwater systemStormwater Treatment

Performance Assessment of Underground Stormwater Treatment Devices

Researchers developed a universal method for evaluating the performance of underground stormwater treatment devices in retaining sediment for removal after a storm event. The method was the first of its kind and was endorsed by ASTM.


Technical Summary: 200746TS (PDF) | Full Report: 2007-46 (PDF)


“This research developed standardized testing procedures that can be effectively used in evaluating underground stormwater treatment systems directly and effectively.”

– Sue McDermott, City Engineer, Avondale, Arizona; Former Public Works Director, City of Mendota Heights

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Components of the WIM systems.Weigh-in-Motion System

Development of a PC-Based Eight-Channel Weigh-in-Motion System

Researchers developed technology for a WIM system that can be easily built, can record vehicle weight across four lanes of traffic and does not need to use actual vehicles to calibrate. The system is much less expensive and easier to modify than a proprietary system.


Technical Summary: 200745TS (PDF) | Full Report: 2007-45 (PDF)


“We’ve proven that you can create a user-friendly and accurate WIM system for a much lower cost than buying a proprietary system. Mn/DOT stands to save a lot of time and money by implementing this system.”
- Alan Rindels, Senior Engineer, Minnesota Department of Transportation

Researchers worked with Metro Transit to identify and analyze problematic bus routes.Intelligent Transportation Systems

Using Intelligent Transportation Systems Data to Improve Transit Performance and Management

Researchers analyzed the data collected by automatic vehicle location and automatic passenger counter systems on a Metro Transit bus route to understand and address its service reliability issues, developing a study methodology that can be applied to improve additional routes.


Technical Summary: 200744TS (PDF) | Full Report: 2007-44 (PDF)


“The methodology developed in this project has the potential to allow transit agencies to use today’s data to improve tomorrow’s service. We hope this research can be applied to commercial software to give agencies more immediate feedback.”

–Sarah Brodt Lenz, Program Administrator, Mn/DOT Office of Transit

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The semi-circular bend test is used to measure the fracture energy of mixture specimens, which is related to resistance to crack propagation.Asphalt Pavement Cracking

Investigation of Low-Temperature Cracking in Asphalt Pavements

In the cold climates of the northern United States, asphalt pavements are susceptible to low-temperature cracking. This study identified simple laboratory tests for predicting the fracture resistance of asphalt mixtures, procedures that were found to correspond to field performance.


Technical Summary: 200743TS (PDF) | Full Report: 2007-43 (PDF)


“This was an excellent start to developing ways to predict and combat low-temperature cracking. The fracture toughness test gave us good results that matched pavement performance.”

– Benjamin Worel, Operations Engineer, Mn/DOT


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This study found the Canada thistle plant to be the most invasive noxious weed, infesting over 3.5 acres per linear highway mile.Noxious Weeds

Surveying Noxious Weeds in Roadway Rights-of-Way

Mn/DOT District 4 staff used a new sampling procedure to locate and measure infestations of noxious weeds and concluded that examining a greater number of much smaller areas, selected with regard to ecozone, was more accurate and would allow for better targeting of weed control resources.


Technical Summary: 200742TS (PDF) | Full Report: 2007-42 (PDF)


“We can now walk 225 feet instead of a quarter mile to collect the data we need to determine the extent of our weed problem, which herbicides to use, and how to distribute them for the most effective treatment.”

– Tina Markeson, Mn/DOT Senior Natural Resource Forestry Specialist




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Simulator participants were monitored for speed, intersection crossing behavior, and the ability to maintain safe headway while distracted by an on-dashboard task.Toward Zero Deaths (TZD)

Rural and Urban Safety Cultures: Human-Centered Interventions Toward Zero Deaths in Rural Minnesota

To help Mn/DOT shape safety interventions, rural and urban respondents answered survey questions about driving risks and behaviors. A small group then underwent driver testing in simulated urban and rural environments. Rural drivers were found to have lower perceptions of driving risk, and the rural environment appears to encourage unsafe speed choices and intersection crossing behavior, particularly among teen drivers.


Technical Summary: 200741TS (PDF) | Full Report: 2007-41 (PDF)


“Too many fatalities are happening on rural two-lane highways. Is that because rural drivers don’t drive as well as others? This study showed that that was not the case.”

– Mike Wagner, Highway Engineer, Nicollet County

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The database groups test sections by project. The Research Study Groups page describes each project and allows users to update data online.Roadway Test Section Database

Minnesota's Transportation Research Site Database

During a five-year project, researchers created and populated a database of the many roadway test sections created for research projects across Minnesota over the last several decades. This maximizes test section investments by putting original test data as well as more recent observations of test sites within the reach of city, county and state engineers.


Technical Summary: 200739TS (PDF) | Full Report: 2007-39 (PDF)


“To gain acceptance with city and county engineers, the database has to be simple to navigate and needs to be publicized regularly. If they start using it for research, they’ll see it’s also available for them to enter in their own test sections.”

– Lou Tasa, Mn/DOT District State Aid Engineer

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PST in MN wetland restoration area

Invasive Species

Biological Control of Canada Thistle

Researchers investigated the effectiveness of the recently discovered biological control agent PST for the control of Canada thistle in roadside rights-of-way and prairie wetland restoration systems, and found that an integrated management system based on PST has a significant impact on the management of this weed.


Technical Summary: 200738TS (PDF) | Full Report: 2007-38 (PDF)


“Although we did not find the silver bullet, this study is a valuable stepping stone to future efforts to use PST as a cost-effective and environmentally friendly way to manage Canada thistle.”

– Paul Walvatne, Mn/DOT Roadside Vegetation Management Unit Supervisor

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The new measurement system can be fitted on full-size snowplows and delivers real-time surface friction readings to an automatic control system that dispenses deicing chemicals.Winter Road Maintenance

Using Real-Time Road Condition Measurements for Automated Winter Road Maintenance

Researchers developed and tested a first-of-its-kind measurement system that, when mounted on snowplows, produces real-time measurements of the tire-road friction coefficient. These measurements are used to automatically adjust the application of deicing chemicals, which allows deicing materials to be used more efficiently and reduces environmental damage from chemical runoff.


Technical Summary: 200737TS (PDF) | Full Report: 2007-37 (PDF)


“The best part about this technology is that we can reduce the amount of salt and chemicals that are applied to roadways during the winter without compromising safety.”

– Rajesh Rajamani, Professor, University of Minnesota Department of Mechanical Engineering

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CPT data acquisition systemSoil Testing

Can Cone Penetration Testing Measure the Resilient Modulus of Soils?

Researchers evaluated the feasibility of using Cone Penetration Testing data to estimate resilient modulus in the field and to identify organic soils. Results show that while the statistical analysis model used by researchers was not sufficient to evaluate resilient modulus or organic soil content, this study provides groundwork for enhancing this model to further the use of CPT in the field.


Technical Summary: 200736TS (PDF) | Full Report: 2007-36 (PDF)


“This report did not establish a link between resilient modulus and CPT test results. Many problems must still be overcome before CPT measurements can aid pavement design.”

– Bruce A. Chadbourn, Mn/DOT Assistant Pavement Design Engineer

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A falling-weight deflectometer tests stiffness by dropping a weight onto a loading plate on the pavement surface and recording the pavement and base response with sensors.Aggregate Base Materials

Measuring the Material Properties of Aggregate Base Containing Recycled Materials

Researchers performed both field and laboratory measurements of resilient modulus for three reconstructed roads that used recycled asphalt paving material in the pavement base, and also performed modulus, shear strength and deformation tests on reclaimed aggregate base and recycled asphalt mixed at various ratios. This established procedures and generated necessary inputs for Mn/DOT’s pavement design manual.


Technical Summary: 200725TS (PDF) | Full Reports: 2007-25, 2007-05 (PDF)


“We needed to know how recycled material compared with virgin material, and we can now look at the relative stiffness values between the two.”

– Shongtao Dai, MnROAD Research Operations Engineer

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bridge planBridge Research

Incorporation of Fatigue Detail Classification of Steel Bridges into the Mn/DOT Database

This project produced a framework for enumerating and ranking bridge details that are prone to fracture and fatigue. Such a ranking system will assist in targeting funds and resources to the most vulnerable bridges and in evaluating requests for load limit increases.


inspector noteTechnical Summary: 200722TS (PDF) | Full Report: 2007-22 (PDF)



“The districts are handling maintenance and inspections well. This ranking tool provides more information to us in the bridge office, helping us start with what’s important in considering safety, inspections and load-increase requests.”

– Jim Pierce, Mn/DOT Bridge Management Engineer




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Small (1.5-inch) WAAS-enabled GPS units mounted on bicycles tracked commuter routes and speeds.Bicycle Commuting

Commuter Bicyclist Behavior and Facility Disruption

Researchers tracked bicycle commuters’ behavior using small Global Positioning System receivers enhanced by a wide-area augmentation system to better understand how infrastructure improvements and disruptions impact cyclists. Small GPS units offer an accurate and affordable method for tracking commuter behavior and will provide transportation planners with data to help prioritize infrastructure improvements.


Technical Summary: 200715TS (PDF) | Full Report: 2007-15 (PDF)


“The methodology is probably the most important outcome here: It proved that using GPS units to track bicycle commuter behavior can work. We also learned how to make it work better in the future.”

– Darryl Anderson, State Bicycle and Pedestrian Coordinator, Mn/DOT Office of Transit

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Reoverlay can be a cost-effective fix for deteriorated decks. In the final step (above), the new overlay is applied.Bridge Maintenance

Repair or Replace Concrete Bridge Decks?
Methods to Select the Lowest Cost Alternative

Researchers performed an economic analysis to identify the most cost-effective maintenance strategies for a large group of aging concrete bridge decks. Based on current prices, researchers determined that repair is preferable to redecking if repair can elevate a deteriorated deck to an acceptable condition. Researchers also developed least-cost repair/replacement strategies for all of the decks in the group.


Technical Summary: 200714TS (PDF) | Full Report: 2007-14 (PDF)


“This study provides helpful information to fall back on when we’re deliberating about using a particular maintenance action.”

– Paul Kivisto, Mn/DOT Metropolitan Region Bridge Engineer

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A water truck and road-reclaimer blended the ash, water and reclaimed pavement materials on 7th Avenue in Waseca.Fly Ash

Demonstration of Ash Utilization in Low Volume Roads

Coal fly ash was used to stabilize reclaimed pavement materials in two Minnesota construction projects to demonstrate the viability of this practice. The ash-treated materials displayed improved stiffness, and analysis of leached moisture did not reveal unsafe trace element levels.


Technical Summary: 200712TS (PDF) | Full Report: 2007-12 (PDF)


“Fly ash is particularly useful for city and county roads that have lower traffic volumes, since agencies need to use locally available materials and keep costs down.”

– John Siekmeier, Mn/DOT Senior Research Engineer

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a sheared soil specimen

Pavement Design

Pavement Design Using Unsaturated Soil Technology

A new method of using the principles of unsaturated soil mechanics during pavement design was developed. This will allow pavement engineers to better take into account field conditions and seasonal variations in moisture content. The new models developed in this study allow pavement designers to estimate the stiffness and strength of any soil encountered in the field.


Technical Summary: 200711TS (PDF) | Full Report: 2007-11 (PDF)


“The constitutive models help us understand the effects of moisture we see during field tests. This allows us to be more confident that our pavement performance estimates are reasonable, and we can now better quantify the effects of moisture during construction quality assurance.”

– John Siekmeier, Mn/DOT Senior Research Engineer


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dust control treatment truckIntelligent Compaction (IC)

Field Validation of Intelligent Compaction

Researchers evaluated intelligent compaction monitoring technology used in earthwork construction for quality control and assurance. They found that while IC technology is a feasible alternative for quality control and potentially quality acceptance, some challenges remain in validating IC rollers to accurately interpret their measurements.


Technical Summary: 200710TS (PDF) | Full Report: 2007-10 (PDF)


“This project provides the foundation for current efforts to implement intelligent compaction and light weight deflectometers in Minnesota.”

– John Siekmeier, Mn/DOT Senior Research Engineer

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IRI smoothness data can be collected using high-speed, van-mounted laser systems, which excel at detecting the types of roughness experienced by vehicle occupants.Concrete Pavement Evaluation

Implementing the International Roughness Index for Concrete Pavement Evaluation

Mn/DOT was trying to improve its method for awarding bonuses to contractors for especially smooth concrete pavement. Investigators compared the old method for measuring smoothness to the new International Roughness Index standard, looking at how each pavement analysis method depicts various surface imperfections and evaluating the different options for implementing IRI incentives.


Technical Summary: 200709TS (PDF) | Full Report: 2007-09 (PDF)


“Highway 59 in Morris, for instance, exhibited ‘chatter phenomena’ due to a basic wave form in the pavement surface, but it had passed incentives under the PI metric. Because of this, we knew we needed to change the incentive specification to an IRI metric.”

– Bernard Izevbekhai, Principal Research Operations Engineer, Mn/DOT

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Investigators simulated impacts on computerized models to gauge probable amounts of deformation in real pedestrian bridges.Pedestrian Bridges

Improving the Strength and Stability of Prestressed Concrete Through-Girder Pedestrian Bridges

Because of a growing concern about the overall safety of pedestrian bridges, investigators used laboratory studies and computer simulation to gauge their ductility, strength and stability as compared with AASHTO specifications. Results showed that several modifications to AASHTO bridge specifications will make future pedestrian bridges stronger and more resistant to collapse.


Technical Summary: 200708TS (PDF) | Full Report: 2007-08 (PDF)


“This was a very valuable study on a topic that has seen very little research. The design changes will improve the strength and flexibility of prestressed concrete through-girder pedestrian bridges built in Minnesota.”

– Jihshya Lin, Mn/DOT Bridge Design Unit Leader

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Minnesota’s current Accident Report form does not include fields for recording information such as the presence or absence of a bicycle lane, which would help Mn/DOT understand the factors that contribute to crash rates.Pedestrian and Bicycle Safety

The Safety of Pedestrian and Bicycle Travel in Minnesota: Inventory, Analysis and Prospectus

Researchers scanned the available sources of accident data involving bicycles and pedestrians for trends such as correlations between accidents and neighborhood attributes. They examined current accident data collection and made recommendations to increase the quantity, quality and use of bicycle and pedestrian crash data.


Technical Summary: 200704TS (PDF) | Full Report: 2007-04 (PDF)


“This project brought together the leaders of many Minnesota organizations around the idea that we need to pay more attention to bicycle and pedestrian safety.”

– Darryl Anderson, Mn/DOT State Bicycle and Pedestrian Coordinator

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Researchers analyzed the safety effects of adding left-protected signaling and other countermeasures to high-speed intersections.Left-Turn Signal Safety

Measuring the Safety Effects of Signal Installation and Left-Turn Phasing Schemes

Researchers analyzed before-and-after crash data, and used statistical analysis and computer modeling to measure the safety effectiveness of Mn/DOT’s practices for signal installations and left-turn signal phasing schemes at highway intersections. The research findings were roughly consistent with Mn/DOT’s guidance and practice in these areas; analysis should be repeated in several years when more after-treatment data are available.


Technical Summary: 200703TS (PDF) | Full Report: 2007-03 (PDF)


“For those situations where we had sufficient data, our findings were basically consistent with Mn/DOT’s current guidelines for the use of protected left-turn phasing on higher-speed highways.”

– Gary Davis, Professor, University of Minnesota Department of Civil Engineering






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The increase in average commute duration is shown by county from 1990 to 2000.Commute Times

Factors Affecting Commute Times in the 1990s

The average length of time it took Minnesota workers to commute to work increased about 2.5 minutes during the 1990s, a larger-than-normal increase. Unidentified factors other than urban sprawl and traffic congestion were thought to be creating a significant shift in commuter behavior. A detailed statistical analysis showed little correlation between economic factors and commute times, and that some of the increase was due to a change in methodology in the 2000 census.


Technical Summary: 200702TS (PDF) | Full Report: 2007-02 (PDF)


“This valuable research into statewide commuting patterns will help us with general transportation planning in the future.”

– Deanna Belden, Economic Policy Analyst, Mn/DOT Office of Investment Management






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This screen shot from MnCMAT shows wide-area crash locations using the stacker feature. In Version 3.7.0E, MnCMAT automatically restacks the map when the user selects a different filter.Crash Mapping Analysis Software

Putting Research into Practice: Updating Minnesota’s Crash Mapping Analysis Tool

The Minnesota Crash Mapping Analysis Tool is a geographic information system-based mapping tool used by Minnesota city and county engineers and other traffic safety professionals to analyze crash data and produce maps, charts and reports of selected crash data. The objective of this project was to augment MnCMAT with current and additional historical crash data, and implement a series of updates that enhance the user interface to better meet user needs.


Technical Summary: 2007RIC09TS (PDF) | Full Report: 2007RIC09


“MnCMAT is very easy to use. Within a few hours, a user can confidently enter queries and generate reports.”

– Mark Vizecky, Traffic Safety Support Engineer, Mn/DOT State Aid Division

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A geogrid can be used within an aggregate layer for reinforcement. The training described appropriate materials and techniques for each geosynthetics application.Geosynthetics Training

Putting Research into Practice: Training Module for Designing and Constructing with Geosynthetics

A geosynthetics expert leveraged decades of Mn/DOT research and federal guidance to create a one-day seminar that described the range of geosynthetics applications occurring throughout Minnesota, such as pavement reinforcement and pavement layer separation, and presented guidelines for materials, design, installation and inspection for each use.


Technical Summary: PP07GEOTS (PDF) | Training Module: PP07GEO (PDF)


“There are so many ways to use geosynthetics. We wanted to provide a resource to explain where and how it has been used to help city and county engineers determine the proper materials and installation techniques for their particular need.”

– Lou Tasa, Mn/DOT District State Aid Engineer

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